Memoirs presented to the Cambridge philosophical society on the occasion of the jubilee of Sir George Gabriel Stokes, bart., Hon. LL. D., Hon. SC. D., Lucasian professor.

DISCHARGE OF AN AIR CONDENSER, WITH A DETERMINATION OF "v." 185
Thus the capacity of the condenser proper is
10 (59-74 + -58) x (59-64 + -58)
47r x '5001
and this reduces to 5779 centimetres.
To this has to be added a term for the proximity of the case to the edges, especially
for the proximity of the floor; the floor correction is
5 x 60 x 72
-4 x 2 — = 6'9 centires.
4 x 2'5
The walls and roof together amount to 8'7, or altogether 15 6 centims.
Next, the ebonite distance pieces must be allowed for. They are each ~ square
centim. in area, and there are 50 of them; their specific inductive capacity may be
taken as 3, so the extra capacity due to them is 8 centims.
Adding all these we get for the condenser capacity, 5803 centims.
Then there is a correction for the charged portion of the wires leading from the
condenser and coil to the spark knobs. This was approximately 7'3 metres long and
one millimetre thick, with a span of 1~ metres between it and the walls. Its capacity
730
was therefore = 50 centims.
2 loge 150
Thus the whole electrostatic capacity under charge was
5853 centimetres.
Connexions were as in Figure 12. The machine was usually connected only across
an air space by needle points so as to take no part in the discharge.
'". I
FIG. 12,
VOL. XVIII. 24